Cyclohexylated diaryl ethers



Patented Mar. 26, 1940 CYCLOHEXYLATED DIARYL ETHERS Frank B. Smith, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Michigan N Drawing.

Application February "26, 1938, Serial No. 192,857

9 Claims, (o1. zet -s12) V This invention concerns certain new chemical products, namely diaryl ethers substituted in either or both of thearyl nuclei by one or more cyclohexyl or substituted cyclohexyl groups. The invention also concerns a method for making such new substituted diaryl ethers. 3

These compounds and their mixtures vary in physical characteristics from high-boiling, viscous liquids to resinous solids or semi-solids, They are substantially insoluble in water but are $01- ub'le in a number of organicsolvents, e. g. benzene, toluene, xylene, etc. They maybe employed directly as'dielectric agents and are also useful as chemical agents from which a variety 15 of other products, e. g. dyes, etc., may be prepared. The liquid products are stable at high temperatures and are adapted for use as heat transfer or storage agents. They also have high dielectric strengths and low power factors, and "are difiicultly flammable and non-corrosive. Hence, they are particularly well adaptedvfor use as liquid insulating and cooling mediums in electrical devices such as transformers, capacitors, switches, etc. Some of the solid products are, colorless, transparent resins having consider I able plasticity, and can be employed in the manufacture of plastic products, coating compositions for insulating use, etc. I

' The aforesaid new compounds are preferably prepared by reacting a diaryl ether or alkyl sub.- .stituted 'diaryl 'ether,' e. g. diphenyl ether, 4-

"methyl-diphenyl ether, etc., with cyclohexene or a hydrocarbon-substituted. cyclohexene in the presence of a catalyst capable of promoting alkylation reactions; e. g. aluminum chloride;

aluminum bromide; ferric chloride; boron trifiuoride; activated bleaching earths such' as Re 'ways in which the principle of my invention has trol or Tonsil; etc. If desired, however, other agents capable ofintroducing the cyclohexyl or e. g. cyclohexylchloride, 3-methyl-cyclohexyl bromide, 2.4diethyl-cyclohexyl-chloride, etc.,

maybe employed.

.The reactantsmay be employed in any desired proportionsdepending upon the products de- 45 sired...,For example, a molecular excess of diphenyl ether may be reacted with cyclohexene 1 ,decreasing the amount of diphenyl ether em- :ployed or by reacting the cyclohexene with the substituted cyclohexyl group in aromatic nuclei, ing the same:

A larger proportion of the poly-substituted compounds may be obtained by separator.- The reaction mixture was mainmonoand di-substituted compounds obtained from a previous run. Ordinarily, I prefer to employ between 0.3 and 1.5 moles of the diary] ether and between 0.1 and 0.5 mole of the lowerboiling fractions from a previous run per mole "5 of cyclohexene or substituted cyclohexene. The

amount of catalyst varies with the particular 250 C. but somewhat higher temperatures may '20 be employed if desired. The reaction is usually complete in from one to twenty hours, although the timemay be shortened considerably by carrying the reaction out under pressure in a closed reactor. After completion of the reaction, the (25 catalyst is removed and the reaction mixture distilled under vacuum.

The distilled products are ordinarily employed directly as dielectric mediums, heat transfer agents, etc., without further purification. If so desired, however, they may be fractionally distilled into fractions representing isomeric monosubstituted diaryl ethers, isomeric di-substituted diarylethers, etc. Also, such isomeric mixtures may be further fractionated toobtain the L35 individual compounds contained therein.

The following examples will illustrate various been applied but are not to be construed as limito Ewample 1 A mixture of 148 lbs. of diphenyl ether, 10 lbs. of Retrol, and 84.1bs. of a mixture of monoand di-cyclohexyl-diphenyl ethers obtained from a previous run was charged into a reactor fitted with a reflux condenser, water separator, thermometer, and stirrer. The mixture was heated to 190 C., and lbs. of cyclohexene was added with stirring over a period of 1.5 hours, during which time the'temperature rose to 210 C. and O thereafter dropped to 200 C. During addition of thecyclohexene, the water contained in the catalyst distilled oil and collected in the water tained at 200 C. with stirring for 16 hours, after which time it was filtered while hot to remove the catalyst. The .crude productthus obtained was a clear, lemon yellow, viscous liquid. It was fractionally distilled under vacuum to obtain the following fractions:

dropping funnel over a period of 1.5 hours, during which time the temperature of the mixture rose to C. After addition of the cyclohexene, the mixture was slowly heated to 250 C. over a period of 7.5 hours. The reaction mixture was cooled, washed with water to remove the catalyst,

Table Fraction No 1 2 3 i 5 6 Residue Product Um'eaeted DPE. Mono cyclo- Monoand di- Di-cyclohexyl Tri-cyclohexyl Poly cyclo- Poly cyclohexyl DFE. glglghexyl DPE. DPE. hexyl DPE. hexyl DPE. Boiling point Up to 200 C. at 200230 O. at 23027?; O. 273300 0. 300 at 20 mm. 293330 C. Above 330 C.

20 mm. 20 mm. at '20 mm. at 20-min. tr; 5293 C. at 5 mm. at 5 mm.

- a mm.

Yield 29 lbs 57 lbs 85 lbslbs 28 lbs .56 lbs 17 lbs. Physical appear- Crystalline solid. Water-W11 ite Wat er-white Very viscous Clear, color- Pale yellow Brittle amber ance. mobile liquid. viscous liqwater-white less semiresin resin.

Sp. gr. 60/60 C 1.0277 Viesggsgyin cps. at .23 344 at 100 C... Refractive index 1.5693 1.5679 1. 1.5662; 1.5523 at 60 1.5530 at 60 at 25 0. C. 0. Percent power'fac- 0.0055 0.0031 0.179 0.184 0.318-; V

Dielectric constant 3.06 3.11 2.91 2.84 2.42

Norm-In the above table DPE means diphenyl ether.

The three mono-cyclohexyl-diphenyl ether isomers were isolated by further fractional distillation of Fraction No. 2. Ortho-cyclohexyl-diphenyl ether was obtained as a thin, water-white liquid, distilling at 2l2-215 C. under 20 millimeters pressure, and having a specific gravity of 1.050 at 25/25 C., and an index of refraction,

The meta-cyclohexyl-diphenyl ether distilled at 220-224 C. under 20 millimeters pressure, and had a specific gravity of 1.051 at 25/25" 0., and an index of refraction,

Para-cyclohexyl-diphenyl ether was obtained as a clear, colorless liquid, distilling at 227-230 C. under 20 millimeters pressure, and having a specific gravity of 1.051 at 25/25 C., and an index of refraction,

Example 2 cyclohexyl-diphe'nyl ethers, 88 grams of a mixture of isomeric di-cyclohexyl-diphen'yl ethers, and 225 grams of more highly substituted products.

Example 3" 170 grams of diphenyl ether. which had been saturated with 3 grams of boron trifluoride was placed in a flask fitted with reflux condenser, stirrer, thermometer, and droppingfunnel. 1164 grams of cyclohex'ene was added slowly from the refractive index,

and fractionally distilled as follows:

Fraction Boiling point Product 1 Up to 200 at 20 mm Unreacted diphcnyl ether. 2 200230 C. at 20 mm Thin colorless liquid. 3 230260 C. at 20 mm... Slightlyi viscous colorless lqLll v 4 262 at 20 mm.-203 C. at Colorless viscous liquid.

- mm. 5 293330 O. at 5 mm Pale yellow resin.

Example 4 A mixture of 40 grams (0.236 mole) of diphenyl ether and 1.2 grams of Retrol was placed in a flask fitted with dropping funnel, reflux condenser, stirrer, and thermometer, The mixture was heated to about C. and 85 grams (0.519 mole) of 3-cyclohexyl5cyclohexene was added gradually with stirring over a period of 1 hour, during which time the temperature rose to 200 C. After removal of the catalyst, the reaction mixture was separated from the unreacted 3- cyclohexyl-cyclohexene by fractional distillation. The fraction boiling above 200 C. under 20 millimeters pressure was a dark amber, viscous oil,

consisting mainly of isomeric di-'(3-cyclohexyl-' cyclohexyl diphenyl ethers, together withsmall amounts of isomeric monoand poly-(3-cyclohexyl-cyclohexyl-) 'diphenyl ethers. It had a specific gravity of about 0.9968 at 60/60 C., a

viscosity of about 400 centipoises at 60 C., and a Example 5 A mixture of 56.0 grams (0.335 mole) of diphenyl ether and 1.7 grams of Retrol was heated as in Example 4., and 123.8 grams"(0i73' 7 mole) of 3-methyl-cyclohexene'added gradually with stirring. The mixture was maintained at 200 C. for 4 hours, after which the catalyst was removed by filtration and the reaction mixture was fra'ctionally distilled. The fraction boiling above 'C.under 20 millimeters pressure, comprising a major proportion of isomeric di-(3- methyl-cyclohexyl-) diphenyl ethers and smaller amounts of isomeric llllOllO- and poly-(3-methylcyclohe'xyl-) diph'enyl ethers, was a dark, viscous oil, having a specific gravity of about 1.064 at 40. v p r A mixture of 28.2 grams (0.111mole) of alpha- 2,195,3ss t Y Y catalyst filtered off. The product thus obtained f (226 grams (1.43 moles) of l-pheny1-cyc1o hexene was added over a period of one hour to a heatedv mixture of 110 grams (0.649 mole) of diphehyl ether and 3.3 grams of Retrol. During the addition the temperature roseto 220 C. The reaction mixture was separated from the catalyst and fractionally distilled under vacuum. 'Ihe fraction distilling above 200C. under 20 millimeters pressure was a dark amber viscous oil, havinga specific gravity of about 1.056 at 60/60 C., a viscosity of about 3800 centipoise's at 60 (3.,

and an index of refraction,

It consisted of amixture of mono-, di-, and poly- (1-phenyl-cyclohexyl-) diphenyl ethers.

- Example-7 A mixture of 50.2 grams (0.228 mole) of alphanaphthylphenyl ether and 1.2 grams of Retro] was heated to 200 C. as in Example4, and 33.2 grams (0.410 mole) of cyclohexeneadded with stirring over a period of 20 minutes. The reac- The fraction. distilling above 210 C. under 20 millimeters pressure com prised a mixture of isomeric monoand poly-- 'cyclohexyl-alpha-naphthyl-phenyl was a straw-colored oil, having a specific gravity of vaboutLO'Z at 60/60 0., a viscosity of about ethers. It

2040 centipois'es at 60C., and an index of're fraction, y 1

beta-di-naphthyl ether and 1 gram of Retrol was f heated to 200 C. and 18 grams (0.222 mole) of cyclohexene added. over a period of- 0.5 hour. After completion of the reaction, the mixture .was filtered and distilled as in Example 4. The

distilled product, comprising a mixture of isomeric monoand poly-cyclohexylealpha betadinaphthyl ethers, was 'a' straw-colored semisolid, distilling above 260 C;. under 1 millimeter pressure, and having a specific gravity of 1. 10? at 100/100 C. I The invention is not limited to the simple diaryl ethers, but may be applied to hydrocarbonsubstituted diaryl ethers. For examp1e4-methy1- diphenyl ether, Z-ph'enyl-diphenyl ether, 2.2-dimethyl di alpha-naphthyl ether, 2-cyclohexyldiphenyl ether, etc., may be reacted with cyclohexene or a hydrocarbon-substituted cyclohexene to prepare the corresponding substituted ethers.

Examples 9 and 10 are illustrative of thepreparation of such substituted diaryl ethersz;

0 Example 9 was a dark red, fluorescent oil. It was fractionally distilled into. the following fractions:

I A mixture of 345 grams (1.52 moles) of 4-terv l at C'., and an index of refraction, tion, mixture was filtered from the ca'talyst and v 'fractionally distilled.

ltiary butybdiphenyl ether and 10 grams of Retrol washeated to 200 C. and 270 grams (3.34 moles) of "cyclohexerie addedslowly with stirring oil,, .comprising isomeric mixtures of monoand.

-poly-cyclohexyl-4-t'ertiary-butyl-diphenyl ethers. 'It'hadfa specific gravity of about 1.020% at lnithe iollowing claims the: expression cycloalkylated diaryl ether in which the alicycliclsub:

stituent contains 6 carbon atoms refers tosimple or hydrocarbon-substituted-' diaryl ethers, e. g.

ZA-dimethyI-diphenyl ether, 4-methyl- -diphenyl j ether, 4-phenyl-dinaphthyl ether," etc.; in. which at least one nuclear hydrogen atom has beensubmethod herein disclosed or the materials employed, provided the step or steps stated by any 10f the following claims be employed or the product' claimed inany of the following claims obtained.

' I therefore particularly point out and distinctlyclaim as my invention: 1 V v 11'. A cycloalkylated diaryl etherinwhich the alicyclic substituent contains 6 carbon atoms in a saturated ring.

2.,A mixture of non-uniformly cycloalkylated diaryl ethers inwhich the alicyclic substituent contains 6 carbon atomsin a saturated ring.

3...A cycloalkylated diphenyl ether in which the alicyclic substituent contains 6 carbon" atoms in a saturated ring.

4."A mixture of non-uniformly cycloalkylated diphenyl ethers in which the alicyclic substituent contains 6 carbon atoms in a saturated ring.

' 5. A cyclohexylated diaryl ether.

. "56. A mixture of non-uniformly cyclohexylated' diaryl others.

7.'Cyc1ohexylated diph'enyl ether.- 8. Cyclohexylated phenyl-diphenyl ether.

FRANK B Fraction Boiling point Specific gravity Product 1 250262 C. at 1.083 at 2.5/25 C-.. 1 Um'eacted phenl 20mm. yl-diphenyl 1 ether. '2"; 2l0-340 C. at 1.050 at 5l/25 O Mono-cyclohex- 5 mm. f yl-phenyl-diphenylethers. 3 Above 340 C. Poly-cyc1ohexyl-- at 5 min. phenyl diphcnyl others.

Example 10 stituted by a cyclohexylv or .hydrocarbon-sub- 'fstituted cyclohexyl group, e. g. B-rnethylcyclo h xyl, 

